Millions of protective garments are used each year to protect workers from a myriad of hazards including chemicals, physical and thermal stresses, biological challenges, and radiological hazards. Applications include general maintenance activities, automotive paint spray and finishing, pesticide application, chemical processing and manufacturing, hazardous waste handling, treatment, and disposal, emergency response, hospitals and EMS, pharmaceutical manufacturing and cleanroom applications, military situations, and innumerable other scenarios. The complexity of exposure scenarios combined with the manufacturing limitations of available polymer and rubber technologies has forced end-users to integrate various personal protective equipment components into an ensemble that together offers the necessary level of protection to ensure the health and well being of the wearer.
Traditionally, the above-mentioned hazards have been addressed separately by manufacturers and users alike. That is, protective equipment has been developed to address the radiological protective needs in the medical industry, the chemical protective needs in the chemical manufacturing industry, and the thermal and physical protective needs in the steel industry. When multiple hazards are confronted, such as is the case in industrial and military chemical/biological response, users have been left to integrate multiple pieces of protective equipment in an attempt to minimize the deleterious effects of the greatest hazards.
The increased threat of international and domestic terrorism has expanded the need for protective clothing beyond traditional boundaries, and towards individuals and workplaces that in the past had no need for such specialized equipment. This expanded threat now includes non-traditional targets that can hold large numbers of civilian personnel such as airports, professional sports stadiums, large office complexes and buildings, government facilities, and non-combative military and quasi-military installations. Combined with the new target sites for CBRNC events is the expanding threat of alternative and multi-functional hazards on the part of international terrorists. The daily threat exists for the use of chemical, biological, and radiological threats especially those associated with “dirty” bombs.
The daily threat of multiple hazards is not new. Numerous manufacturing facilities around the world contain a combination of chemical, biological, and radiological agents that if involved with an industrial accident can and do create multi-hazard release scenarios for emergency responders. While various protective garments exist to address many of the specific hazards present in controlled and uncontrolled exposures to chemical, biological, and radiological hazards, limited attempts have been made to adapt these items to collectively protect a worker. Of particular concern is the explicit omission of certain hazards from the primary industrial performance based standards for emergency responders, that being the National Fire Protection Associations (NFPA) 1991—Standard on Vapor-Protective Ensembles for Hazardous Chemical Emergencies. This standard in the industry recognized document for hazmat first responders. While this document addresses many of the protective needs of first responders, it explicitly omits any relevance to radiological hazards which is an obvious threat to applicable responders. While numerous high chemical barrier fabrics have been developed for civilian and military use, none yet have been developed that can address the collective needs of a multi-hazard CBRNC event.
The U.S. Environmental Protection agency (USEPA), through their Standard Operating Guidelines, have put forth a generic strategy for defining what they term “Levels of Protection” (LOPs). These LOPs revolve around generic types of respiratory protection, as defined by the Occupational Safety and Health Department (OSHA) and the National Institute for Occupational Safety and Health (NIOSH), and generically described chemical protective clothing, recommended for certain chemical handling activities. The protective clothing industry has and continues to use these guidelines to generically describe the types of garments to be used under various use scenarios.
Level “A” is defined as the highest level of respiratory and chemical protection incorporating supplied air (i.e., SCBA or airline respirator) and a fully encapsulating, gas-tight suit. Level “A” ensembles offer the wearer protection against both liquids and vapors. The interface between the glove and sleeve are gas and liquid-tight, typically consisting of a circular plastic or metal glove-ring that is used as a form around which the glove and sleeve are fitted and than secured with a worm-drive or stepless ear hose-clamp. Level “A” type garments are used by highly trained individuals in situations involving unknown chemicals and a variety of other exposure scenarios involving high exposure potential and carcinogenic hazards. These readily available garments vary in price from about $500 to about $3500, and are available from a variety of manufacturers such as DuPont (USA), Lakeland Industries (USA), Trelleborg (Sweden), Respirex (United Kingdom), Auer (Germany), Draeger (Germany) as well as others. Base fabrics of construction include both lightweight high-chemical barrier composites such as Responder® (DuPont) and TyChem® 10,000 (DuPont), to heavier-weight elastomers such as Viton® and Chlorobutyl from Trelleborg. While offering the highest level of protection to the wearer from both the design/configuration and fabrics of construction, Level A garments are expensive, difficult to don/doff, require an annual inspection program, consume a fairly large volume for the purposes of storage, and require respirator fit testing and medical clearance on the part of the wearer prior to use.
The next lower level of protection described by EPA is Level “B”, which is described as requiring the same respiratory protection as Level “A” but with a lesser degree of chemical protection, typically not fully-encapsulating. A traditional Level “B” ensemble includes a self-contained breathing apparatus (i.e., SCBA), a sealed-seam, limited-use coverall with an attached hood, storm-flap, and attached booties, and separate chemically resistant gloves and elastomeric over-boots. It has become common practice to use duct-tape over the glove-sleeve and boot-leg interfaces to minimize penetration of chemicals onto the wearer's skin and clothing. Level “B” type garments are available from a wide variety of manufactures fabricated from an even wider array of base materials both film-based and elastomeric.
EPA's Level “C”, describes a lesser level of protection than Level B, and includes a lower degree of respiratory protection (i.e., air-purifying respirators), however with similar clothing requirements as in Level “B”. Since the chemical hazards and exposures scenarios requiring Level “C” protection are less hazardous than Level “B”, “taping” is less common but still used. Level “C” type garments are available in a variety of configurations both one piece and multiple piece, fabricated using a variety of protective fabrics, and incorporating several types of seams, which all affect the ultimate protection afforded the wearer. Unlike Level “B” garments, which are most often constructed using a sealed seam, Level “C”, garments are offered with sealed, bounded, and simple sewn seams. Any non-sealed seam, by construction, has the potential for allowing influx of hazardous chemicals, thus exposing the wearer.
Level “D” protection is the lowest level of protection described by EPA and is used in situations where there is no risk of respiratory exposure and very limited potential for exposure to low hazard chemicals. Chemical protective clothing is allowable under Level “D”, however, rarely worn.
The protective needs of the chemical industry are fairly well met with an array of fabrics, materials, and protective items available to the industrial and military user communities. The majority of chemical protective clothing used by general industry is based on “barrier” technology. Barrier technology hinges on the principle that the protective material essentially blocks the transport of a chemical through the material. The chemical resistance of “barrier” type materials is dictated by Fick's Law of Diffusion, and the solubility of the chemical hazard(s) in the polymer matrix of the protective material. The industry standard used for evaluating chemical resistance is the American Society for Testing and Materials (ASTM) F739—Standard Test Method for Resistance of Protective Clothing Materials to Permeation by Liquids and Gases. This method is applicable to essentially any chemical and all chemical forms (i.e., solids, liquids, and gases).
Numerous attempts have been made to develop chemical protective fabrics that offer a wide range of chemical resistance. Examples of such fabrics are described in Bartasis (U.S. Pat. No. 4,920,575), Blackburn (U.S. Pat. No. 5,035,941), Hauer et al. (U.S. Pat. No. 5,626,947), Hendriksen (U.S. Pat. No. 5,059,477), Langley (U.S. Pat. Nos. 4,833,010, 4,855,178, and 5,948,708), Sahatjian et al. (U.S. Pat. No. 4,943,473), Shah (U.S. Pat. No. 4,755,419), van Gompel (U.S. Pat. No. 4,753,840), as well as many others, the contents all of which are incorporated herein by reference in their entireties.
Each of the above mentioned approaches incorporates various types of continuous single and multiple layered chemical barriers, and strength enhancing substrates, scrims, and reinforcing base fabrics to achieve the desired level of chemical resistance and physical durability while maintaining acceptable flexibility. These and other “barrier” approaches today make up what is termed the limited-use chemical protective clothing market. Hazardous material emergency response requires a degree of preparedness that can only be achieved by utilizing protective products that offer performance to a wide range of response scenarios. The most widely used chemical garments offer this type performance and are composed of multiple polymer composites comprising barriers such as polyvinyl chloride, chlorinated polyethylene, chlorinated butyl, polyethylene, high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, polyurethane, PTFE, combinations thereof, or multiple-layered coextruded films which include one or more layers of ethylene-vinyl acetate, ethylene vinyl alcohol, polyvinyl alcohol, nylon, ionomers, polyester, polyvinylidine chloride, PET, liquid crystal polymers, metallized films, fluoro-chemical based films, and/or blends thereof. These products offer a broad range of chemical resistance and have proven effective in chemical response scenarios, but are essentially useless when exposed to ionizing radiation.
The protective needs of the radiological industry are being met to a lesser degree. It is common practice to address radiological hazards from the perspective of time, distance, and shielding. That is, limit the overall time of exposure to a source, maximize the distance between the source and the affected individual(s), and finally shield the source from the work environment. Protective clothing can be categorized under the “shielding” aspect of this three step protective strategy.
Radiation can generally be classified as ionizing and non-ionizing. Protective strategies and equipment employed to address these types of radiation are very different due the differences in the human response and the overall control of the sources. Common non-ionizing sources include solar and manmade UV irradiation and electromagnetic radiation (i.e., radio frequency and microwave). Physiological response to non-ionizing radiation is more chronic in nature and occurs over repeated exposures over a long duration. The protective requirements to limit this type exposure can be met with barrier creams in the case of UV exposure, and lightweight metallized fabrics, textiles, and films for electromagnetic radiation such as are described by Reynolds (U.S. Pat. No. 3,164,840) and Ebneth (U.S. Pat. No. 4,572,960), Vaughn (U.S. Pat. No. 5,275,861) as well as others.
Ionizing radiation presents a greater and more immediate risk upon exposure including decapacitation and under extreme conditions death. As such, ionizing radiation is a more obvious choice during terrorist activities. Sources for ionizing radiation include military weaponry, nuclear power plants, and medical x-rays. The requirements for protection within nuclear plants is achieved primarily through shielding while a combination of shielding (i.e., drapes & curtains) and partial body protective devices are used within the medical arena. Protective shielding materials fabricated with lead and lead oxides, examples of which are described by Maine (U.S. Pat. No. 3,093,829), Weir (U.S. Pat. No. 5,525,408), and Yamamoto (U.S. Pat. No. 4,740,526) have dominated this market. As mentioned above, since the source and path of ionizing radiation is typically closely controlled it has been common practice to use partial body protective covers to shield those areas of the body that are particularly susceptible to ionizing radiation including the thyroid area, male and female gonadal regions, and the breast area. Exemplary partial body covers and aprons are described by Herbert (U.S. Pat. No. 4,417,146), Cusick (U.S. Pat. No. 4,843,641), Stein (U.S. Pat. No. 4,924,103), Caldwalader (U.S. Pat. No. 5,523,581), Sheehy (U.S. Pat. No. 5,778,888), and Tone (U.S. Pat. No. 5,073,984). While practical in partial body configurations and designed for very short term use, these fabrics and items are of little use in uncontrolled industrial and military CBRN events. Furthermore, there are inherent toxicological risks and disposal issues involved with the use of lead and derivative type materials and products.
Significant progress has been made in addressing the toxicity issues surrounding lead-containing radiation protective materials. Numerous alternative radiopaque materials exist that can replace lead in radiation attenuation applications. Lagace (U.S. Pat. No. 6,153,666) describes several alternative radiation attenuating additives including barium sulfate or other barium salts, tin, boron or its compounds, bismuth compounds, or other heavy metals including antimony, bismuth, gold, thallium, tantalum, uranium, zirconium or non-metals such as iodine. Lagace goes on to state that barium sulfate has become a preferred attenuant as disclosed by Shah (U.S. Pat. No. 5,245,195), Orrison (U.S. Pat. No. 4,938,233), and Hirai (U.S. Pat. No. 4,203,886). DeMeo (U.S. Pat. Nos. 6,281,515 and 6,459,091) disclose the use of barium compounds as attenuants in breathable medical devices such as facemasks.
Lagace presents a comprehensive overview of the myriad of polymer matrices that can be used as carriers of the radiation attenuants including thermoplastic materials such as polyolefins including polyethylene and polypropylene, vinyl polymers such as polyvinyl acetate and vinyl acetate copolymers, acrylic polymers such as polymethylenthacrylate, and certain thermoset polymers such as silicones, urethane polymers, and elastomeric materials such as styrene-butadiene rubber, styrene-isoprene rubber, polybutadiene, polyisoprene, butyl rubber, epoxy polymers and the like.
It should be evident from the above discussion that an immediate need exists for products designed and configured so as to offer multi-functional resistance to a wide range of CBRN hazards. The present invention addresses many of the limitations of existing protective strategies as well as the related prior art and puts forth an improved composite fabric that offers universal protection against a wide range of military chemical agents, toxic industrial chemicals and materials (TICS and TIMS), biological agents, as well as certain ionizing and non-ionizing forms of radiation.